Patent GB-191001125-A (GB)
Title: Improvements in Aeroplanes.
Inventor: RIESTER ANDRE
IPC: B64C11/00
Filed: 1910-01-15
Granted: 1910-09-01
Abstract: 1125. Riester, A. Jan. 16, 1909, [Convention date]. Screw propellers.-The inclination of the blades of a screw propeller is adjusted either automatically or by hand so that the propeller exerts that maximum thrust corresponding to the speed of the motor. The spindles 2, Fig. 10, of the propeller blades are mounted in bearings 5 and provided with arms 3, which are connected by rods 4 to an adjustable sleeve 6. The sleeve 6 is surrounded by a collar 8 connected to a lever 9, by which the sleeve is moved to adjust the inclination of the blades. The lever 9 is connected to the armature of a solenoid 11 included in a circuit controlled by the thrust of the propeller. The lever 9 may also be controlled manually by a lever 14 connected to the armature 12. The propeller shaft is mounted in bearings 17, 18. The bearing 18 is formed as a thrust bearing and comprises a piston 24 which presses against a liquid, such as oil, in a chamber 25 connected to a manometer 26, Fig. 12, by a pipe 27. A spring 21 bears at one end against a rotary block 22 and at the other end against the sleeve 6, tending to reduce the inclination of the blades. The pipe 27 is connected to a fixed hollow piston 59, Fig. 17, on which can slide a cylinder 60 adapted to compress a spring 61. The automatic control of the maximum thrust comprises a centrifugal governor 30 driven from the motor and carrying a contact 38 adapted to establish electrical connexion with a plate 39. The governor 30 is connected by a bell-crank lever 31 with a sliding rod 32 carrying pivoted metal fingers 34, 35 controlled by springs 40, 41. The fingers are provided with an insulated portion 42, 43 and with spring studs 46, 47 provided with an adjustable head 48, Fig. 18, adapted to bear against metal strips inserted in insulating-blocks 49, 50. A metal rod 57 carrying contacts 58 is fixed in an insulated manner to the finger 34. When the motor starts, the increase in the propeller thrust causes the cylinder 60 to move over the piston 59 and moves a finger 62 at the end of the cylinder into contact with the prong 64 of a fork 65 secured to a rod 66, one eud of which is formed as an armature for a solenoid 70. This closes the circuit including the solenoid 11, Fig. 10, so as to increase the inclination of the propeller blades, the circuit comprising battery 71, line 72, cylinder 73, finger 62, prong 64, rod 66, line 74, copper strip 56, line 75, copper strip 53, contact pins 46 and finger 34, strip 54, line 76, solenoid 11, line 77, governor 30, contact 38 and line 78. The solenoid 11 remains energized until the maximum thrust of the propeller for the speed of the motor has been reached, and when the thrust begins to diminish owing to the blades assuming too great an inclination, the spring 61 moves the finger 62 to the left thus breaking the circuit of the solenoid 11 and allowing the spring 21, Fig. 10, to reduce the inclination of the blades. This results in a rcduction in the thrust of the propeller and the finger 62 is moved into contact with the prong 63, again completing the circuit of the solenoid 11, and so increasing the inclination of the blades. An increase in the thrust of the propeller then moves the finger 62 to break the circuit so that the finger 62 oscillates between the positions 62<11> and 62<111> corresponding to the maximum thrust for the speed of the motor. If the speed of the motor increases, the governor 30 moves the rod 32 to the right and the friction of the studs 47 on the plate 50 causes the finger 35 to lag momentarily in its movement and to assume the position 35<1>. The solenoid 11 is then energized through the line 79, studs 47 and finger 35, strip 56, line 75 and the remainder of circuit described above. By this means the thrust of the propeller is increased so that the finger 62 is moved into contact with the prong 64 and the maximum thrust of the propeller for the increased speed is obtained and maintained as before described. If the speed of the motor decreases, the governor 30 moves the rod 32 to the left and the finger 34 lags in its movement, assuming the position 34<1>. During this movement the insulated rod 57 connects by means of the studs 58 the strips 51, 52, and closes the circuit of the solenoid 70 through the lines 79, 80, 81, 82 and 78. The solenoid 70 draws its armature 69 to the left and moves the prong 64 into contact with the finger 62. The solenoid 11 is thereby energized through the circuit first described, and the inclination of the blades is adjusted to correspond with the reduced speed of the motor.